Patient-specific femoral guide

ABSTRACT

A medical device for preparing an elongated bone, such as a proximal femoral bone, for receiving an implant includes a patient-specific femoral guide and an elongated alignment element. The femoral guide has a patient-specific three-dimensional bone-engaging surface configured according to a preoperative plan based on a three-dimensional image model of the femoral bone to mate complementarily with the surface of the proximal femoral bone extending between the greater trochanter, the femoral neck and the femoral shaft of the proximal femur. The femoral guide includes a first guide end forming a planar guide configured for guiding a neck resection. The alignment member can be removably attached to the femoral guide and defines a reference axis for guiding a cutting tool into the femoral bone through a resected surface of the femoral neck.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/446,660, filed on Feb. 25, 2011.

This application is a continuation-in-part of U.S. application Ser. No.12/978,069 filed Dec. 23, 2010, which is a continuation-in-part of U.S.application Ser. No. 12/973,214, filed Dec. 20, 2010, which is acontinuation-in-part of U.S. application Ser. No. 12/955,361 filed Nov.29, 2010, which is a continuation-in-part of U.S. application Ser. Nos.12/938,905 and 12/938,913, both filed Nov. 3, 2010, and which arecontinuation-in-part of U.S. application Ser. No. 12/893,306, filed Sep.29, 2010, which is a continuation-in-part of U.S. application Ser. No.12/888,005, filed Sep. 22, 2010, which is a continuation-in-part of U.S.application Ser. No. 12/714,023, filed Feb. 26, 2010, which is acontinuation-in-part of U.S. application Ser. No. 12/571,969, filed Oct.1, 2009, which is a continuation-in-part of U.S. application Ser. No.12/486,992, filed Jun. 18, 2009, and a continuation-in-part of U.S.application Ser. No. 12/389,901, filed Feb. 20, 2009, which is acontinuation-in-part of U.S. application Ser. No. 12/211,407, filed Sep.16, 2008, which is a continuation-in-part of U.S. application Ser. No.12/039,849, filed Feb. 29, 2008, which: (1) claims the benefit of U.S.Provisional Application No. 60/953,620, filed on Aug. 2, 2007, U.S.Provisional Application No. 60/947,813, filed on Jul. 3, 2007, U.S.Provisional Application No. 60/911,297, filed on Apr. 12, 2007, and U.S.Provisional Application No. 60/892,349, filed on Mar. 1, 2007; (2) is acontinuation-in-part U.S. application Ser. No. 11/756,057, filed on May31, 2007, which claims the benefit of U.S. Provisional Application No.60/812,694, filed on Jun. 9, 2006; (3) is a continuation-in-part of U.S.application Ser. No. 11/971,390, filed on Jan. 9, 2008, which is acontinuation-in-part of U.S. application Ser. No. 11/363,548, filed onFeb. 27, 2006, now U.S. Pat. No. 7,780,672 issued Aug. 24, 2010; and (4)is a continuation-in-part of U.S. application Ser. No. 12/025,414, filedon Feb. 4, 2008, which claims the benefit of U.S. ProvisionalApplication No. 60/953,637, filed on Aug. 2, 2007.

This application is continuation-in-part of U.S. application Ser. No.12/872,663, filed on Aug. 31, 2010, which claims the benefit of U.S.Provisional Application No. 61/310,752 filed on Mar. 5, 2010.

This application is a continuation-in-part of U.S. application Ser. No.12/483,807, filed on Jun. 12, 2009, which is a continuation-in-part ofU.S. application Ser. No. 12/371,096, filed on Feb. 13, 2009, which is acontinuation-in-part of U.S. application Ser. No. 12/103,824, filed onApr. 16, 2008, which claims the benefit of U.S. Provisional ApplicationNo. 60/912,178, filed on Apr. 17, 2007.

This application is also a continuation-in-part of U.S. application Ser.No. 12/103,834, filed on Apr. 16, 2008, which claims the benefit of U.S.Provisional Application No. 60/912,178, filed on Apr. 17, 2007.

The disclosures of the above applications are incorporated herein byreference.

INTRODUCTION

The present teachings provide a patient-specific alignment and resectionguide and associated tools for guiding a resection of the femoral neckand aligning a broach or other cutting instrument or tool along theproximal femur in preparation for a femoral implant.

SUMMARY

The present teachings provide a medical device for preparing anelongated bone, such as a femoral bone, for receiving an implant. Themedical device includes a patient-specific femoral guide and anelongated alignment element. The femoral guide has a patient-specificthree-dimensional bone-engaging surface configured according to apreoperative plan based on a three-dimensional image model of a proximalfemoral bone to mate complementarily with the surface of the proximalfemoral bone extending between the greater trochanter, the femoral neckand the femoral shaft of the proximal femur. The femoral guide includesa first guide end forming a planar guide configured for guiding a neckresection. The alignment member can be removably attached to the femoralguide. The alignment member defines a reference axis for guiding acutting tool into the femoral bone through a resected surface of thefemoral neck.

In some embodiments, the medical device includes a cutting tool, such asa broach or reamer, for example, for preparing the proximal femoral boneafter the neck resection, a driver tool for holding and driving thecutting tool into the femoral bone along a first axis, and a connector.The connector can be slidably coupled to the alignment member and to thedriver tool. The connector has a patient-specific distance between thefirst axis and reference axis for guiding the cutting tool into thefemoral bone through a resected surface of the femoral neck at aposition determined during a preoperative plan based on thethree-dimensional image model of the femoral bone.

The present teachings provide a method for preparing a proximal femoralbone for an implant. The method includes attaching a patient-specificfemoral guide to the proximal femoral bone, guiding a cutting instrumentalong a planar cutting guide of the femoral guide, and cutting thefemoral neck along a patient-specific plane using the cutting guide. Themethod also includes coupling a cutting tool to a driver tool, andslidably connecting the driver tool to an alignment member extendingfrom the patient-specific guide along a reference axis such that thecutting tool is automatically positioned at a preselected distance fromthe reference axis and at a preselected location relative to theresected femoral neck. The method includes preparing the femoral bonefor receiving an implant using the cutting tool.

Further areas of applicability of the present teachings will becomeapparent from the description provided hereinafter. It should beunderstood that the description and specific examples are intended forpurposes of illustration only and are not intended to limit the scope ofthe present teachings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present teachings will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is an environmental view of a patient-specific femoral guideaccording to the present teachings;

FIG. 1A is a perspective view of an exemplary femoral guide according tothe present teachings;

FIG. 1B is a perspective view of another exemplary femoral guideaccording to the present teachings;

FIG. 2 is an environmental view of the patient-specific femoral guide ofFIG. 1 shown with a driver holder and a cutting tool;

FIG. 3. is a side view of the driver holder for the cutting tool of FIG.2; and

FIG. 4 is a side view of the cutting tool of FIG. 2.

DESCRIPTION OF VARIOUS ASPECTS

The following description is merely exemplary in nature and is in no wayintended to limit the present teachings, applications, or uses.

The present teachings provide a patient-specific alignment and resectionguide and associated tools for guiding a resection of the femoral neckand aligning a broach or other cutting tool along the proximal femur inpreparation for receipt of a femoral implant.

As described in commonly assigned U.S. application Ser. No. 11/756,057,filed on May 31, 2007, during a preoperative planning stage, imagingdata of the relevant anatomy of a patient can be obtained at a medicalfacility or doctor's office. The imaging data can include, for example,a detailed scan of a pelvis, hip, knee, ankle or other joint or relevantportion of the patient's anatomy. The imaging data can be obtained usingMRI, CT, X-Ray, ultrasound or any other imaging system. The imaging dataobtained can be used to construct a three-dimensional computer image ofthe joint and prepare an initial pre-operative plan that can includebone or joint preparation, including planning for resections, milling,reaming, broaching, cutting, implant selection and fitting, design ofpatient-specific guides, templates, tools and alignment protocol for thesurgical procedure.

Computer modeling for obtaining three-dimensional computer images of therelevant patient's anatomy can be provided by various CAD programsand/or software available from various vendors or developers, such as,for example, from Materialise USA, Ann Arbor, Mich. The computermodeling program can be used to plan a preoperative surgical plan,including planning various bone preparation procedures, selecting ordesigning/modifying implants and designing patient-specific guides andtools including patient-specific prosthesis components, andpatient-specific tools, including reaming, broaching, milling, drillingor other cutting tools, alignment guides, templates and otherpatient-specific instruments.

The pre-operative plan can be stored in any computer storage medium, ina computer file form or any other computer or digital representation.The pre-operative plan, in a digital form associated with interactivesoftware, can be made available via a hard medium, a web-based or mobileor cloud service, or a cellular portable device to the surgeon or othermedical practitioner, for review. Using the interactive software, thesurgeon can review the plan, and manipulate the position of images ofvarious implant components relative to an image of the anatomy. Thesurgeon can modify the plan and send it to the manufacturer withrecommendations or changes. The interactive review process can berepeated until a final, approved plan, is sent to a manufacturingfacility for preparing the actual physical components.

After the surgical plan is approved by the surgeon, patient-specificimplants and associated tools, including, for example, alignment guides,cutting/milling/reaming/broaching or other tools for the surgicalpreparation of the joint or other anatomy portion of the specificpatient can be designed using a CAD program or other three-dimensionalmodeling software, such as the software provided by Materialise, forexample, according to the surgical plan. Patient-specific guides andother instruments can be manufactured by various stereolithographymethods, selective laser sintering, fused deposition modeling or otherrapid prototyping methods. In some embodiments, computer instructions oftool paths for machining the patient-specific guides and/or implants canbe generated and stored in a tool path data file. The tool path data canbe provided as input to a CNC mill or other automated machining system,and the tools and implants can be machined from polymer, ceramic, metalor other suitable material depending on the use, and sterilized. Thesterilized tools and implants can be shipped to the surgeon or medicalfacility for use during the surgical procedure.

Patient-specific implants, guides, templates, tools or portions thereofare defined as those constructed by a surgical plan approved by thesurgeon using thee-dimensional images of the specific patient's anatomy.These patient-specific components have a three-dimensional engagementsurface that is made to closely conform, contact and mate substantiallyas a negative mold of corresponding complementary portions of thepatient's anatomy. The complementary anatomy can include bone surfaceswith or without associated soft tissue, such as articular cartilage, forexample, and inner surfaces of different bone density, such ascancellous and cortical bone.

Referring to FIGS. 1 and 2, an exemplary patient-specific femoral guide100 for a proximal femur 80 is illustrated. The femoral guide 100 isdesigned to have a three-dimensional patient-specific bone engagementsurface 102 designed during the pre-operative plan from thethree-dimensional image of the specific patient's hip joint with orwithout associated cartilage or other soft tissue. The femoral guide 100can be in the form of a thin curved shell 101 having a first guide end104 or guide side 104 (in the form of a slot or an edge, as discussedbelow) forming a planar resection guide for resecting the femoral neck84 at a location and orientation relative to first and second referenceaxes A and B along a resection plane R and creating a resected surface88. The location and orientation of the resection plane R is determinedin the pre-operative plan using the three-dimensional image of thepatient's joint to conserver bone, remove abnormalities, conform to orcorrect anteversion angle or other orientation of the femoral neck.

Referring to FIGS. 1 and 1A, the shell 101 can be in the form of atwo-piece clamshell with couplable anterior and posterior components 103a, 103 b that can engage the anterior and posterior surfaces of theproximal femur 80 with corresponding patient-specific engagementsurfaces 102 to nestingly and securedly engage the bone. The shell 101can include a second end side 106 defining an opening for a greatertrochanter 82 and a third end side 108 defining an opening for a femoralbone shaft 90. Similarly, the first guide end 104 can be in the form ofan opening defining an annular resection plane or guide R. The edge ofthe first guide end 104 can be made thicker or reinforced or with anadded flange for additional stability during resection. The shell 101can be additionally secured to the proximal femur 80 with one or morebone screws or pins 116 passing through a hole 112. The anterior andposterior components 103 a, 103 b can be movable connected, for example,along a lateral side 107 with a hinge or other connector 111 permittingpivoting, clamping, snap-on or other connection. The anterior andposterior components 103 a, 103 b can be connected to one another or tothe bone with fasteners or pins passing through holes 113′ along theopposite or medial side 109, or with a snap-on or other connection toone another.

Alternatively, the shell 101 can include a single one-piece component103, which can be attached to only the anterior (or only the posterior)surface of the proximal femur 80 with bone fasteners or pins insertedthrough hole 112 and other corresponding holes, as discussed above. Inthe embodiment in which the shell 101 includes a single component 103,as shown in FIG. 1B, the single component 103 can partially wrap aroundfrom the lateral and medial sides 107, 107 toward the posterior (oranterior) surface of the proximal femur 80 along curved lateral andmedial flanges 117 and 119. In the single-component embodiment, thefirst guide end 104, second end side 106 and third end side 108 can bein the form of edges or partial openings or slots, rather than openingswith a closed periphery. Additional holes 113′ and 113″ can be used forfastening the alignment guide 100 to the lateral and medial sides 107,109.

With the femoral guide 100 secured on the proximal femur 80, a cuttingblade or saw or other surgical instrument can be guided by the firstguide end 104 to cut the femoral neck 84 along a resection plane R,thereby removing the femoral head 86 and exposing the resected surface88 of the femoral neck 84, as shown in FIGS. 1 and 2. After resection,the femoral guide 100 can be used to guide instruments for preparing theproximal femur 80 for a femoral implant, as discussed below. Asdiscussed above, the resection plane R is selected during pre-operativeplanning to conserve healthy bone, adjust or conform to patient-specificanteversion or other angles and in conformance with the planned implantsfor the femoral joint. When the femoral guide 100 is attached to thefemur intra-operatively, the resection plane R is automaticallydetermined by the first guide end side 104.

The femoral guide 100 can include an elongated alignment member 130,such as a rod or bar, which can be attached to the shell 101 with bolts,screws, clamps or other fasteners 114 at a portion 115 of the shell 101between the first and second end sides 104, 106 of the shell 101 andthrough holes 133 of the alignment member 130. The attachment positionof the alignment member 130 at portion 115 is determined during thepre-operative plan and such that the alignment member 130 defines areference axis A, when the shell 101 is attached to the proximal femur80. The reference axis A can coincide or be parallel to theintramedullary axis of the femoral shaft 90, as shown in FIGS. 1 and 2and can be used to reference the position for a cutting tool or broach200 for preparing the proximal femur 80 to receive a femoral andintramedullary implant, as discussed below. In this regard, thealignment member 130 can include a scale 138 for showing the advance orposition and insertion level of the broach 200 relative to the bone, anda stop element 132 indicating when a full seated position of the broach200 is reached and broaching is completed. The alignment member 130 canbe either permanently or removably attached to the femoral guide 100,such that the alignment member 130 can be optionally attached to thefemoral guide 100 after the femoral head 86 is resected using thefemoral guide 100. The alignment member can have a round cross-section,or alternatively, a rectangular or otherwise keyed cross-section, asdiscussed below.

Referring to FIG. 2, a driver tool 300 for holding a broach or reamer orother cutting tool 200 can be slidably coupled to the alignment member130 using a connector 134. The connector 134 is designed during thepre-operative plan to locate the driver tool 300 and the broach 200 at apreselected distance and orientation relative to the reference axis A,such that the broach 200 can automatically engage the resected surface88 of the femoral neck 84 at a location and orientation determinedduring the pre-operative plan. For example, when the connector 134 iscoupled between the alignment member 130 and the driver tool 300, adistance D between the reference axis A and a longitudinal axis C of thedriver tool 300 equals a value determined during the pre-operative planfor positioning the broach 200 in a pre-planned position and orientationfor preparing the proximal femur 80 to receive an implant. When theconnector 134 reaches the stop 132, the sliding motion of the connector134, the driver tool 300 and the broach 200 is arrested and depth islimited to the desired depth to accommodate a pre-determined positioningof an implant according to the pre-operative plan. The alignment member130 can be rotationally keyed to the connector 134 to allow motion onlyalong the reference axis A, i.e., to prevent or reduce any rotationalinstabilities during use. For rotational stability, other than circularcross-sections for the alignment member 130 can be used, such as, oval,triangular or polygonal, for example.

The connector 134 can be an elongated element, such as a bar, having anopening 136 for receiving the alignment member 130 therethrough. Theconnector 134 can be coupled to the driver tool 300 with a clamp, bolt,screw, snap fit, forked end connector or other coupling device 137.

Referring to FIG. 4, the broach 200 can include have a body 201 with anouter peripheral three-dimensional cutting surface 202 extending from aproximal end surface 204 to a distal end surface 210 of the body 201.The cutting surface 202 is provided with cutting teeth and channels orgrooves 211 for moving bone chips away from the cavity created by thebroach 200.

Referring to FIGS. 2-4, the broach 200 can be coupled to the driver tool300 by providing a coupling interface between the proximal end surface204 of the broach and a distal surface 314 of the driver tool 300. Thecoupling interface can include, for example, a finger or rod or otherprotrusion 208 extending from the proximal end surface 204 of the broach200 to be received in a corresponding bore or other opening 312 definedthrough the distal surface 314 of the driver tool 300. The couplinginterface can also include an opening or bore 206 defined through theproximal end surface 204 of the broach 200 for receiving a distalportion 316 of a retractable bar or rod 310 of the driver tool 300. Thedriver tool 300 can include a body 302, a handle bar 304, and a proximalflange 318 for impaction. The retractable rod 310 can extend along thebody 302 and is biased by a proximal spring 308. The retractable rod 310can be deployed for engaging the broach 200 by using a trigger 306 whichcan be operated by holding with one hand the handle bar 304 andsqueezing the trigger opening 305 with an index finger and move thebroach 200 form a first to a second position along the axis C. Thebroach 200 can be held securely with the driver tool 300, as shown inFIG. 2 and inserted through the resected surface 88 the femoral neck 84to prepare the femoral bone 80 for receiving a femoral implant. Thedepth of insertion of the broach 200 can be monitored by the scale 138and the broach 200 can be removed after the connector 134 reaches thestop 132. In some embodiments, the broach 200 can be patient-specificand designed during the pre-operative plan to conform to an innerboundary surface of the femur, which is imaged and selected during thepre-operative plan.

The patient-specific femoral guide 100 can be manufactured frombiocompatible materials using machining, rapid manufacturing bystereolithography, laser welding, or computer-assisted manufacturingusing numerical machining or robotic controllers.

The foregoing discussion discloses and describes merely exemplaryarrangements of the present teachings. Furthermore, the mixing andmatching of features, elements and/or functions between variousembodiments is expressly contemplated herein, so that one of ordinaryskill in the art would appreciate from this disclosure that features,elements and/or functions of one embodiment may be incorporated intoanother embodiment as appropriate, unless described otherwise above.Moreover, many modifications may be made to adapt a particular situationor material to the present teachings without departing from theessential scope thereof. One skilled in the art will readily recognizefrom such discussion, and from the accompanying drawings and claims,that various changes, modifications and variations can be made thereinwithout departing from the spirit and scope of the present teachings asdefined in the following claims.

1. A medical device for preparing an elongated bone for receiving animplant comprising: a femoral guide having a patient-specificthree-dimensional bone-engaging surface configured according to apreoperative plan based on a three-dimensional image model of a proximalfemoral bone to mate complementarily with the surface of the proximalfemoral bone extending between a greater trochanter, a femoral neck anda femoral shaft of the proximal femoral bone, the femoral guideincluding a first guide end forming a planar guide configured forguiding a neck resection; and an elongated alignment member removablyattachable to the femoral guide and defining a reference axis forguiding a cutting tool into the proximal femoral bone through a resectedsurface of the femoral neck.
 2. The medical device of claim 1, furthercomprising a connector couplable to a driver tool for driving a cuttingtool into the femoral bone after neck resection, the connector having anopening slidably receiving the alignment member for guiding a cuttingtool.
 3. The medical device of claim 2, wherein the alignment memberincludes a scale indicating a depth of the cutting tool into the femoralbone.
 4. The medical device of claim 2, wherein the alignment memberincludes a stop for preventing further insertion of the cutting toolinto the femoral bone.
 5. The medical device of claim 4, in combinationwith the driver tool and the cutting tool.
 6. The medical device ofclaim 2, wherein the connector is sized for determining apatient-specific distance between the reference axis and a longitudinalaxis of the driver tool for guiding the cutting tool into apatient-specific position through femoral bone.
 7. The medical device ofclaim 1, wherein the patient-specific three-dimensional bone-engagingsurface of the femoral guide includes surfaces complementary toanterior, posterior, medial and lateral surfaces of the femoral bone forsurrounding the femoral bone.
 8. The medical device of claim 1, whereinthe patient-specific three dimensional bone-engaging surface of thefemoral guide includes a surface complementary to one of the anteriorand posterior surface of the femoral bone.
 9. The medical device ofclaim 1, wherein the femoral guide is formed as a two-piece clamshellincluding an anterior component and a posterior component.
 10. Themedical device of claim 9, wherein the clamshell defines a neck opening,a greater trochanter opening and a femoral shaft opening.
 11. Themedical device of claim 9, wherein the anterior and posterior componentsare movably coupled along a lateral or medial side.
 12. The medicaldevice of claim 1, wherein the femoral guide is formed as a singleone-piece component engageable to one of the anterior and posteriorsurfaces of the proximal femoral bone and extending partly around theother of the anterior and posterior surfaces along medial and lateralsides of the femoral bone.
 13. A medical device for preparing a proximalfemoral bone for an implant comprising: a femoral guide having apatient-specific three-dimensional bone-engaging surface configured tomate complementarily with the surface of the proximal femoral boneextending between the greater trochanter based on a three-dimensionalimage model of the femoral bone, the femoral neck and the femoral shaftof the proximal femur, the femoral guide including a first guide endforming a planar guide configured for guiding a neck resection; acutting tool for preparing the proximal femoral bone after the neckresection; a driver tool for holding and driving the cutting tool intothe femoral bone along a first axis; an elongated alignment memberattachable to the femoral guide and extending along a second axis; and aconnector slidably couplable to the alignment member and to the drivertool and having a patient-specific distance between the first and secondaxes for guiding the cutting tool into the femoral bone through aresected surface of the femoral neck at a position determined during apreoperative plan based on the three-dimensional image model of thefemoral bone.
 14. The medical device of claim 13, wherein thepatient-specific three-dimensional bone-engaging surface of femoralguide includes surfaces complementary to anterior, posterior, medial andlateral surfaces of the femoral bone for surrounding the femoral bone.15. The medical device of claim 13, wherein the patient-specific threedimensional bone-engaging surface of the femoral guide includes asurface complementary to one of the anterior and posterior surface ofthe femoral bone.
 16. The medical device of claim 13, wherein thefemoral guide is formed as a two-piece clamshell including an anteriorcomponent and a posterior component.
 17. The medical device of claim 16,wherein the clamshell is hinged along a lateral or medial side.
 18. Themedical device of claim 13, wherein the femoral guide is formed as asingle one-piece component engageable to one of the anterior andposterior surfaces of the proximal femoral bone and extending partlyaround the other of the anterior and posterior surfaces along medial andlateral sides of the femoral bone.
 19. A method for preparing a proximalfemoral bone for an implant comprising: attaching a patient-specificfemoral guide to the proximal femoral bone; guiding a cutting instrumentalong a planar cutting guide of the femoral guide; cutting a femoralneck of the proximal femoral bone along a patient-specific plane usingthe cutting guide; coupling a cutting tool to a driver tool; slidablyconnecting the driver tool to an alignment member extending from thepatient-specific guide along a reference axis such that the cutting toolis automatically positioned at a preselected distance from the referenceaxis and at a preselected location relative to the resected femoralneck; and preparing the proximal femoral bone for receiving an implantusing the cutting tool.
 20. The method of claim 19, further comprisingmeasuring the advance of the cutting tool with a scale on the alignmentmember.
 21. The method of claim 19, further comprising: indicatingcompletion of cutting using a stop of the alignment member.
 22. Themethod of claim 19, further comprising: coupling a connector between thealignment member and the driver tool, the connector aligning the drivertool at the pre-selected distance from the reference axis.
 23. Themethod of claim 19, further comprising: attaching the alignment memberto the femoral guide after cutting the femoral neck.
 24. The method ofclaim 19, further comprising: attaching a patient-specific engagementsurface of femoral guide to a complementary surface of the proximalfemoral bone.
 25. The method of claim 19, wherein the complementarysurface of the femoral bone includes portions of an anterior and aposterior surface of the proximal femoral bone.
 26. The method of claim19, wherein the complementary surface of the proximal femoral boneincludes a portion of only an anterior surface of the proximal femoralbone.
 27. The method of claim 19, further comprising: surrounding theproximal femoral bone between the greater trochanter and the femoralneck with the patient-specific femoral guide.